Protective Effect of Enterococcus faecium and Its Extracellular Vesicles Against Ethanol-Induced Intestinal Injury

In this study, we examined the impact of Enterococcus faecium (E. faecium, Efm) and its extracellular vesicles (EVs) on intestinal morphological structure, antioxidant function, inflammatory response, and permeability in rats. In a 5-day feeding experiment, a total of 72 female Sprague Dawley (SD) rats were randomly allotted into nine groups with eight rats per group. The study was conducted in three parts. First, we examined the impact of Efm on ethanol-induced intestinal injury. Second, we investigated the protective effects of various active components of bacterial culture on intestinal function in vivo. Third, we explored the impact of Efm with elevated EV secretion on intestinal function. The rats were treated by gavage administration (5 mL/kg body weight [BW]) every other day for a total of three times. After the last treatment at 2 h, the phosphate buffered saline (PBS) group received 5 mL/kg BW of PBS orally, whereas the other groups were orally administered 5 mL/kg BW of absolute ethanol to induce intestinal injury. After the feeding trial, eight rats per treatment were collected for intestinal samples. Our findings demonstrate that pretreatment with Efm can reverse morphological alterations in intestinal tissues, enhance superoxide dismutase/malondialdehyde levels, increase intestinal permeability, and reduce the inflammation levels, thereby regulating intestinal damage. Pretreatment with EfmEVs reversed the detrimental effects of ethanol-induced intestinal damage, displaying a discernible decline in inflammation, augmented permeability, and bolstered antioxidant capacity. Moreover, the release of EVs contributes to the intestinal safeguarding mechanism of Efm. EVs act as mediators in Efm's protective response against ethanol-induced intestinal injury by mitigating inflammation and enhancing antioxidant activity. The Clinical Trial Registration Number: FOSU210403.